Theory

Bulking of fine aggregates(sand) is a phenomenon in which the volume of sand increases when some amount of moisture is added to it. It depends upon the particle type, size and the amount of water content. When fine aggregates are damp or contain excess moisture, they tend to adhere to each other and increase in volume. This phenomenon can lead to inaccurate measurements and proportions in concrete mixtures if not accounted for. Finer is the sand, more will be the bulkage.

The extent of bulking can vary depending on factors like the grading of the sand and the amount of moisture present. It is necessary to determine the bulking of sand before using it at the construction site. Sand is mixed with concrete to fill up the pores and empty spaced and avoid segregation. Bulking of sand is likely to alter the W/C ratio in concrete mix, hence making it harsh and difficult to use. Thus, this experiment gives us an overview of the bulkage value of sand.

To account for bulking in construction practices, engineers and concrete mix designers often adjust the proportions of fine aggregate in the mix based on its moisture content. This adjustment ensures that the correct volume of dry sand is used in the concrete mixture, preventing potential issues such as reduced concrete strength and workability.

The formula for calculating the bulking of sand is -:

   Percentage bulking of sand = (H-H’/H’) ×100 
          

Where,

H is the height of loose sand

H’ is the height of saturated sand